COMPARISON OF PIGMENT PRODUCTION AND MOTILITY TESTS WITH PCR FOR RELIABLE IDENTIFICATION OF INTRINSICALLY VANCOMYCIN-RESISTANT ENTEROCOCCI

Forty-eight clinical isolates identified as either Enterococcus faeciu m or Enterococcus faecalis with the MicroScan system (Dade Internation al, MicroScan Inc., West Sacramento, Calif.) were further characterize d by two supplementary biochemical tests (pigment production and motil ity). Twenty isolates (42%), all initially identified as E. faecium, w ere motile. Of these 20, 8 isolates (17%) produced yellow pigment and were identified as Enterococcus casseliflavus and the remaining 12 (25 %) were nonpigmented and were identified as Enterococcus gallinarum. I dentical identification results were obtained when PCR amplification o f regions of the vanC gene was used as a technique for differentiating these Organisms. The results of this study indicate that motility and pigment production tests together with commercial test systems are su fficient for reliable identifications of E. faecium, E. casseliflavus, and E. gallinarum.